I use the Varia with my 945, it works perfectly. You get the colors, dots for cars, beeps, no problemo. Pairing it is easy too. Just get it you won't regret it.

I hear why folks above have complained about the rule "ride as far right as possible" as being bad, but I think riding as far right as 'practical' pretty much sums it up.

I hate when riders have a perfectly wide, beautiful shoulder (which we do have often here in NorCal), and the cyclists insist on riding as far LEFT as possible, which means they're pretty much 1-2 inches off the right road marking line. This happens more often than not, which means me, as usually the faster rider on the aero TT bike, have to pass in the road, because the few times I've passed on the right because there was an entire car-width space on the right, have gotten me cursed out by the cyclist I pass, even when I announce I'm coming from behind on the right (I understand that, but if he just rode slightly to the right, and not even close to the gutter, I'd easily pass on the left.)

I'm as bike-friendly a driver as they come as well, but it's also a minor pet peeve of mine when I'm driving on a decently busy road with posted speed limits of 50mph, which also has a really large nice shoulder for cycling, and these cyclists again are riding at the leftmost portion of the shoulder, to the point I have to slow down or change lanes as I get near them because they're constantly drifting into the car lane. When you've got a really wide road shoulder (I know, I ride that same route a LOT!), you shouldn't be pushing up on the fast-moving cars.

When there's no shoulder, I'm always super safe and have no problems waiting as long as needed to make a safe pass with the car with ample room. Even if it means backing up some traffic behind me.